I'm over feeling like this. :(

Our friends invited us round for dinner and sleep over for the night. Just after I walked through their door, she told me they are 12 weeks pregnant with twins and they weren't even ttc! 
I love my friend to bits and I am happy for them but now I'm sitting here trying to put a brave face on and keep back the tears. I've been Ttc for over two years. I hate feeling like this, it makes me feel so guilty and like a bitch because I'm sooo jealous and sad for myself. I never used to be the jealous type. I just started to feel strong again after feeling depressed about my infertility last week, and now I'm feeling inadequate again! FML... All I want to do is celebrate with my friend like a normal person but my sadness just takes over automatically. I don't know what to do anymore, I'm so over this. 
Please don't judge me I'm feeling fragile at the moment.